Electric starting-motor



H. STEINHART.

ELECTRIC STARTING MOTOR. APPLICATION rlLcn-nicqz. 1919.

1,386,285 Patented Aug. 2, 1921.

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UNITED TAB- S PATENT. ounce EERMANN s'rEnimT, or s'ru'r'ronn'r, GERMANY, 'AssIoNoR. are THE Emir or 303mm: Boson axrrmensmsonarnor ,S'I'U'I'TGART, GERMANY.

ELECTRIC srAn'rmo-noroa' Speciflcation of'Letters Patent, Y

Patented Aug. 2, 1921.

; Application med December 12,1919. Serial No. 344,500.

To all whom it may concern Be it known that HERMANN STEINHART, a citizen of Germany, residing at and whose post-office address is J agerstr. 40, Stuttgart, Germany, have invented certain new and useful Improvements in Electric Starting- Motors, of which the following is a specification. I g

With starting motors whose pinions are caused to mesh with the teeth of a cogged flywheel of an internal combustion engine by displacing their armatures, the coupling operation is performed either'by pulling the pinion toward, or by pushing it awayfrom, the motor, against the action ofa helical spring which tends to keep the pinion on the armature out of mesh with the fly-wheel.

When the helical spring is placed opposite to the pinion the most obvious arrangement is to cause it to exert pressure when the pinion is drawn in. But a pinion which is arranged to mesh with the flywheel teeth on being pulled inward, i. 0., toward the motor, possesses the disadvantage that it lies above the flywheel of the internal combustion engine when it is in its inactive or normal position, so that, to enable it to mesh with flywheel teeth when pulled inward, these teeth have to be elevated above the periphery of the wheel. Consequently in cases where an engine which'has notbeen designed at the outset for electric starting, is to be subsequently equipped with a starting motor, it is necessary either to provide it with a different flywheel or to fix a special circle of teeth upon the existing flywheel. This disadvantage is absent in the case of a pinion which is caused to mesh by being pushed outward, because such a pinion does not lie above the flywheel but beside it when it isinits inactive or normal position, so that a starting equipment of this kind can be conveniently fitted to an engine at anytime, the flywheel presenting no obstacles. But a disadvantage of pinions which are thrust outwardly was, up to the present, that they were connected with draft springs, which are in themselves disadvantageous because they relax sooner than pressure springs and besides add consider-.

I ably to the length of the casing of the ma chine, because they are arranged at the end of the armature opposite to the inion and involve the use of a special bushing in connection with the motor casing.

In accordance with the invention a pressure spring arranged in the interior of the armature shaft is employed also for outwardly pushed pinions, and at the same time the shortest possible length of the entire starting motor is obtained. This is accomplished by so arranging the pressure spring that it is guided upon a. rod or bolt fixed to the motor casing, and that its one end presses against a fixed head of the bolt in the interior of the shaft. While its other end presses against a movable abutment at an end of the armature shaft.

In the drawing a starting motor is diagrammatically illustrated which is equipped 1n accordance with the invention with a pressure spring and a pinion that is made to mesh with the flywheel teeth by being thrust outward, or away, from the motor.

Revolubly mounted between the pole pieces 6, that are inclosed within the easing a of the starting motor, is an armature 0 which, as long as the pinion d is out of engagement with the flywheel teeth 6, is

kept laterally displaced from the poles b by the hellcal spring 7 arranged in the interior of the hollow armature shaft i. In accordance with the invention the helical spring is slipped onto a guide bolt 9 which is fixed 1n a side plate h of the motor casing and has a head is that forms a fixed abutment for the helical spring, the movable abutment of the spring consisting of a ringl at the end of the hollow armature shaft 2'. The end of the longitudinally displaceable armature shaft is guided by a short bushing m at the side plate h of the motor casing. The engagement ofthe pinion (Z with the flywheel teeth 6 of the internal combustion motor and uncoupling it from the teeth a of the flywheel.

I I claim:

I In combination with a flywheel of an in ternalcombustion engine provided with gear teeth, an electric motor comprising a hollow shaft, a casing, a bolt fixed to the said casing and situated within the said shaft, and to keep the pinion at out of engagement 10 a fixed abutment at the end of the said-bolt, with the teeth on the said flywheel.

a movable abutment at an end of the hollow In testimony whereof I have affixed my shaft, an armature and a pinion on the said signature in presence of two witnesses.

shaft, a field magnet for afi'eeting the said HERMANN STEINHART armature, and a pressure spring arranged upon the said bolt and between the said Witnesses:

abutments and operating to displace the ADOLF LEBHIERS,

armature with respectto the field magnet Monemm S. MEYER. 

